Default action : if the reply is not dropped (only provisional replies can be), it will be injected and processed by the transaction engine.

The main 'onreply_route' identified by 'onreply_route {...}' or 'onreply_route[0] {...}' is executed for all replies received.

Certain 'onreply_route' blocks can be executed by TM module for special replies. For this, the 'onreply_route' must be armed for the SIP requests whose replies should be processed within it, via t_on_reply("onreply_route_index").

6. local_route

The local route is executed automatically when a new SIP request is generated by TM, internally (no UAC side). This is a route intended to be used for message inspection, accouting and for applying last changes on the message headers. Routing and signalling functions are not allowed.